my $sample= [ [5,7,2], [9,4,8], [1,6,3] ];
my @widths= map 0+@$_, @$sample;
my @sort= sort map @$_, @$sample;
$sample= [ map { [ splice @sort, 0, $_ ] } @widths ];

##</code><code>##

use mapcar;
my $sample= [ [5,7,2], [9,4,8], [1,6,3] ];
my @refs= sort {$$a cmp $$b} map \(@$_), @$sample;
mapcar {
    my( $ref, $val )= @_;
    $$ref= $val;
} \@refs, [ map $$_, @refs ];